Study Of Clamping Method For Shape Machining Of CFRP Curved Flexible Parts

Carbon fibre reinforced resin matrix composites(CFRP)are widely used in the aerospace sector due to their light weight,high temperature resistance and high specific strength,in order to achieve weight reduction and efficiency in such high-end equipment.At the same time,in order to ensure that the design structural strength,aerodynamic performance and other indicators after assembly,the CFRP in the aircraft assembly accuracy and efficiency put forward very high requirements,such as 17 meters long,5 meters wide composite wing skin on the seam gap requirements of 2±0.5 mm,and the skin in the direction of the position of the accuracy requirements of not more than 0.5 mm.and the current conformal processing of such components mostly use multi-point However,there are still unclamped areas in the multi-point clamping,which leads to large deformation when processing curved flexible parts and affects their processing accuracy.In this paper,a combined clamping method is proposed,and a set of clamping devices is designed according to the proposed method.Specifically,the overall multi-point flexible clamping is used,while non-contact clamping is used for the local deformation of flexible parts under the overall multi-point flexible clamping,where the local non-contact clamping is a supplement to the multi-point overall clamping.Firstly,a mathematical model is established based on the condition that the deformation of the flexible part under the overall multi-point flexible clamping is minimized and that the flexible part needs to be balanced in the horizontal direction during the machining process,and the number and position of suction cups are analysed and discussed through the model to arrive at the number and distribution of suction cups.The number and position of the suction cups are then checked and optimized by means of hydrostatic simulations.Secondly,as the flexible part will still be deformed under the overall multi-point clamping,the non-contact support method is chosen for the local clamping,considering that the support device will easily scratch the surface of the flexible part during the local contact support.The different non-contact methods are compared,and the structure of the local clamping device is designed.The loadbearing capacity of the local clamping structure is analyzed using a mathematical model and the preliminary structural dimensions of the local clamping are derived.Fluid simulation is established to optimize the structural dimensions of the local clamping device by comparing the support forces generated by the local clamping device structure at different sizes.Establish conformal machining simulations and experiments to derive optimal clamping methods by comparing the magnitude of deformation of flexible parts under different clamping conditions.